Method of making flexible bags



y 16, 1944- A. RAMBOLD 2,349,111

METHOD OF MAKING FLEXIBLE BAGS Original Filed May 3, 1940 2 Sheets-Sheet l wring May 16, 1944., A, RAMBOLD 2,349,111

METHOD OF MAKING FLEXIBLE BAGS Original Filed May 5, 1940 2 Sheet-Sheet 2 ll i- 1 ivlti'or:

A002; fl/wsoza Patented May 16, E944 Adolf iftamboid, Dresden, Geany; vested in the Alien Property Qtodian Qriginal application May 3, 1940, Seriai No. 833,243.. Divided and this application May 31, 1941, Serial No. 396,114 lira Germany May 30,

(till. 93-35) 9 Clas.

This application is a division of my application Serial Number 333,243, filed May 3, 1M0, for Bag with insoluble, automatic fold closing.

The premnt invention relates to the manufacture of folded bags of all types made by folding a blank of material of rectangular design over a core, preferably in such a manner that the bags comprise a smooth continuous bottom, several smooth continuous sides and two opposite continuous sides, which are closed and formed by folding together adjacent edges of the blank of material, and then turning the bag inside out to bring the seams inside the bag, and whereby the bag is held together without any additional aids.

The bag of the present invention is particularly intended for use as an infusion bag for tea, coffee and the like but other uses will readily suggest themselves. Such bags when used as sales packages may be made for example of a suitable material, such as filter paper or perforated Cellophane or cloth. The top closing of said bags can be effected in known manner by means of folding and clamping with staples or by means of sealing the material. In the case of infusion bags, a string holder with a tag can be applied simultaneously with the stapling.

The position of the folded seams bears no relation to the invention and may be arranged as desired.

The successive steps in manufacturing two embodiments of the invention are shown in the accompanying drawings, in which:

Figures 1, 2, 3 and 4 are perspective views showing successive steps in the manufacture of the bag out of a rectangular blank sheet of material over a hollow core of rectangular cross section, Figure 5 shows the step of pushing the formed bag through the hollow-core by means of a plunger, to turn the bag inside out; Figure 6 is a fragmentary perspective view on an enlarged scale showing the result of the step illustrated in Figure 5; Figure 7 shows the completed bag without a top closure; Figure 8 shows the bag filled and provided with a top closure; Figures 9, l0 and 11 are perspective views showing the successive steps used in producing a bag with difierent side fold or side seams; Figure 12 shows the completed bag turned inside out and made according to the method of Figures 9, and 11; Figure 13 shows this bag filled and provided with a top closure; and Figure 14 shows another method of closing the top of the bags.

e the bags shown in Figures 8 and 13 are infusion bags, they can also be used as sales packages as well, and the ratio of their dimensions may be as desired, the drawings not being intended to limit the invention either as to proportions or as to sizes. In manufacturing the bag, a rectangular blank of sheet of material is utilized which is folded in U-fashion in any suitable manner over a core l of rectangular cross section as shown in Figure 1. A hollow core is preferably used. The inner corners of the edges of the core are preferably rounded off, as shown in Figure 6, in order to facilitate the pushing of the completely folded bag through the core as hereinafter described. The area of the blank which corresponds to the bottom of the finished bag is indicated by the numeral 2. The portions of the blank which extend beyond the ends of the bottom area and project beyond the narrow sides of the core I are indicated by the numerals 3 and 4, while the portions of the blank which depend from the longitudinal edges of the bottom area and from the portions 3 and 4,

are indicated by the numerals 5 and 6.

The next step after the folding of the blank on the core as described is to press the portions 9 and it together at the narrow sides of the core so that they extend in a plane passing through the middle of the core and parallel with the wide sides i and 8 of the core, as shown in Figure 2. The portions 9 and it are then folded together several times, in the present examples two times, and the resultant seam is then bent to ,one side to lie along the narrow side of the core 6, as

, shown in. Figure 3. As Figure 3 also shows, portions ll projecting above the bottom 2, are formed by the operation, and the portions H are then folded over onto the bottom as shown in Figure 4. The plunger I2 is then brought down upon the bottom 2, so as to push the bottom followed by the sides of the bag, through the hollow core, thereby turning the bag inside out. The finished side folds or seams G3 are prevented from opening during the operation by the presence of springs or the like It. As Figure 6 shows, the projecting triangular portions ii are brought by this operation into the inside of the bag with the result that the bag remains closed without any additional aids simply by means of its side folds.

In Figures 8 and 13, showing the filled bags with their tops closed in any suitable manner,

a staple i5 is shown securing the top closure seams according to Fig. 9 comprises thrusting the portions 3 and 4, projecting beyond the bottom 2, between the lateral portions 8 and III in such a manner that edges l8 are positioned near the edges of the portions 9 and I so that when the portions 9 and I0 are folded together several times, said portions 3 and l are folded therewith, as shown in Fig. 10. In the present example the portions 9 and III with the portions 3 and 4 are folded twice. The completely folded bag thus formed is shown in Figure 11. The resultant seams are indicated by the numerals l9. When the bag form thus obtained is turned inside out by an operation such as that described hereinabove and shown in Figure 5 of the drawings, triangular portions at the ends of the bottom 2 result from this operation, which connect the bottom 2 and the portions 3 and 4, and which are exposed at the outside of the bag, as shown clearly in Fig. 12. This arrangement secures the folded side seam l9 at the lower end of the bag. It is also to be noted that by this arrangement the outer edge 2| of the fold or seam l9, which, in the unturned bag shown in Figure 11 is located adjacent to one side of the bag, is brought into the inside of the bag, while the inner edge or crease 22 of the fold I9, which is located in the narrow side of the unturned bag, remains in the middle position in the finlshed bag. In closing the bag, as shown in Figure 13, the narrow sides of the bag are indented along the crease 22.

It is to be noted that providing the bag with a top closure serves to increase the security of the side folds or seams for which gluing or stapling have heretofore been required.

While I have described certain preferred embodiments, I desire that it be understood that modifications of my invention may be readily made and I intend no limitations upon my invention other than may be imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A method of manufacturing a bag which comprises folding a blank into U-shape while holding the resultant facing walls apart, then folding adjacent side edges of the walls upon each other to form seams, and then turning the folded blank inside out so as to prevent the seams from opening.

2. A method of manufacturing a bag comprising folding a blank of material into substantially U-shape over a hollow core to form a smooth continuous bottom and opp sed sidewalls, said bottom having portions thrust be.- tween adjacent and portions of the walls and positioned near the edge thereof, said end portions of the walls, together with the bottom added thereto, being folded over and over to form a self-closing seam, and then thrusting the bag thus formed through the hollow core so as to turn the bag inside out and dispose the seam on the inside of the bag.

3. A method of manufacturing a bag of polygonal cross section, comprising forming the bag out of a rectangular blank of material over a hollow core, by folding the blank in U-fashion over the hollow core, in a manner to obtain a smooth continuous bottom and two smooth continuous sidewalls folding upon each other the lateral edges of the sidewalls so as to define two continuous end walls so that sides formed by folding the side edges over and over, whereby the originally free edges of the blank of material are covered by the edge of the resultant fold. and the fold lies along the outside of the end walls, and the folding of the edges of the sidewalls producing triangular portions turning down the triangular portions onto the bottom of the bag, then turning the bag inside out so that said triangular portions and the folds are brought into the inside of the bag.

4. The method of making a bag from a blank of formable sheet material which comprises forming a bag by folding the sheet material with external seams, and turning the bag thus formed inside out with the seams being disposed interiorly of said bag and maintained closed by the formation.

5. The method ofmaking a bag from a blank of formable sheet material which comprises forming a bag by folding the" sheet material. in the general form of a bag but with outwardly flaring portions; further forming the bag by interlapping the flaring portions to provide external seams, such seams being liable to separate under conditions of use of the bag; and then turning the bag thus substantially formed inside out, to lock said seams and prevent their separation in use.

6. Method of making a sheet material bag which comprises folding a blank of the material in U-shape so as to define two spaced sidewalls and a bottom area connecting the sidewalls, said bottom area exceeding in length the area of the intended bag bottom dimension so as to define first foldable portions projecting beyond the intended bag bottom joined to portions of the sidewalls, said sidewalls similarly exceeding the width of the sidewalls of the intended bag, so as to define second foldable portions, then drawing said second foldable portions toward each other into side by side position and folding the resultant several times in a manner to define relatively fiat folded external seams and endwall portions connected by the seams along which the seams lie, the production of the seams resulting in substantially triangular folding of said first foldable portions, bending the resultant triangular portions onto the bag bottom, and then turning the bag inside out so as to dispose the seams and the triangular portions at the inside of the bag whereby the bag resists opening of the seams in service.

7. Method of making a sheet material bag as v recited by claim 6, wherein the triangular portions are disposed externally with respect to the said second foldable portions and reside wholly within the finished bag, as a result of the operation of turning the bag inside out.

8. Method of making a sheet material bag as recited by claim 6, wherein said triangular portions are inserted between the said second foldable portions prior to the folding of said second foldable portions whereby the triangular portions are folded in the folding of the second portions ADOLF RAM'BOLD. 

